It is known in the art relating to rail lubrication to apply a lubricant to locomotive wheels to minimize friction between the wheel flanges and rails, especially on curves. In the early 1980's studies performed by the Association of American Railroads revealed substantial fuel consumption reductions during testing with flange lubrication. The railroad industry quickly adopted equipment mounted on board locomotives. The continuous application of lubricant to the flanges of locomotive wheels and thus the rails is today an industry practice.
Previous systems which have been developed primarily utilize a liquid lubricant such as oil or grease which is sprayed on the wheels. Practical experience has shown that these systems are unreliable and often difficult to retrofit. Much difficulty has been experienced in the application to the trucks of the locomotive due to the clearance considerations and adverse environment which includes high vibrations and severe dirt contamination. Typical grease or oil based systems mount their applicator nozzles on the truck frame of the locomotive which is spring mounted relative to the wheels. Although the vibration environment is improved, the alignment of the nozzles to the wheels is not accurate due to the relative motions of the wheels to the truck frame.
Development of solid lubrication materials to replace the liquids offers potential improvements in delivery accuracy and delivery effectiveness due to reduced fling-off. Solid lubrication materials have been used or tried in the past. Such systems typically were mounted on the truck frame and gravity or spring pressure was used to urge a block of lubricant toward a wheel flange. Alternatively, a guide shoe was used to align the system to the wheel, and a stick of lubricant in a tubular holder was fed against the wheel flange. Mounting on the truck frame inevitably requires some sort of mechanism to compensate for the wheel relative motions. Tracking or complicated guidance mechanisms have typically yielded very poor results.
The application of solid lubrication materials to the wheels presents significant difficulties in positioning, alignment, and durability of the system. In particular, mounting brackets and equipment mounted on the unsprung truck components (wheels and motors) must be durable in the severe environment. It has been proposed to avoid mounting on the truck frame by mounting on an unsprung portion such as the journal box. Particularly, it has been proposed to use a heavy bracket (1/2 inch steel plate) extending horizontally outward from the journal box to the wheel flange area. These types of brackets were found to be too bulky and severe problems with strength of the attachment to the journal box were experienced. Due to large inertial loads developed in the high vibration environment, simple, heavy brackets are not optimal and problems of fatigue and fastener deterioration can be expected.
Applicators for dispensing solid lubricant to the wheel flanges have also been proposed. Even when optimum bracket design is employed there can be some small movement of the wheel relative to the dispenser and, depending on the journal box design, there may be substantial movement. The applicator should be able to compensate for such movement and at the same time should be as close as possible to the wheel flange to avoid a gap which is bridged only by unsupported lubricant.